It's getting very close to that time. In fact, it makes sense to start digging the hole while the ground is still reasonably soft.
So, I thought I would post a cross-section sketch of what an ideal mound looks like.
Unfortunately, I wasn't able to rotate the image.
The depth of the hole is 4', four feet, minimum diameter is 2', two feet, the wider the better. The height of the mound is 2 1/2', two and a half feet, and diameter is 6', six feet. It will need a minimum of 9-12 cubic feet of soil amendments/organic matter. The spiral represents a soaker hose.